First Commercial use for PIM

A polymer invented by academics at the University of Manchester has found its first commercial use in a sensor that identifies when filters in industrial respirators must be changed. The polymer, known as PIM (polymer of intrinsic microporosity), was developed in 2006 in research led by Professors Peter Budd and Neil McKeown. It has a highly rigid and contorted structure with nanometre sized pores which allow penetration of small molecules. “One feature of a PIM is that it really loves small organic molecules and will pull them out of the air or from solution,” said Professor Peter Budd. “The 3M sensor is designed to show a change in colour when organic vapours are adsorbed by the PIM. In order to do this, a very thin film of the PIM is sandwiched between two reflective layers,” he added. Workers in many areas use respirators to protect them from harmful chemical vapours. Organic vapour filters must be discarded and replaced based on exposures and usage, to ensure proper protection. Until now, there has been no visual indicator to help determine when to change an organic vapour filter. “The sensor is designed to give a green colour in the absence of vapour. When an organic vapour is taken up by the PIM, it changes the refractive index, as well as slightly swelling the polymer. Both effects lead to a colour change from green to red,” said Budd. Current research is exploring other applications for PIM, including their use in membranes for separating gas and liquid mixtures. PIMs have the potential for the removal of carbon dioxide from power station flue gases, and for the purification of bioalcohols and in other industrial and pharmaceutical products.